<script type="text/javascript" src="xmlhttp.js"></script>
<script type="text/javascript">
function test(obj)
{
    alert(obj.statusText);
}

XMLHttp.sendReq('GET', './test.htm', '', test);
XMLHttp.sendReq('GET', './test.htm', '', test);
XMLHttp.sendReq('GET', './test.htm', '', test);
XMLHttp.sendReq('GET', './test.htm', '', test);

alert('Pool length:' + XMLHttp._objPool.length);
</script>
<button onclick="XMLHttp.sendReq('GET', './test.htm', '', test);alert('Pool length:' + XMLHttp._objPool.length);">test</button>